1. Field of the Invention
The present invention relates generally to gauges and measuring devices, and more particularly to an adjustably positionable protractor for temporary placement on the end of a section of pipe, for measuring the angle between that pipe and another pipe for fabricating an elbow having the proper angle for joining the two pipes. The present protractor includes a pipe attachment bar for temporary placement across the end of a pipe, with a protractor extension bar or arm and protractor thereon extending from the center of the pipe attachment bar. The assembly includes various adjustments for different pipe diameters, relative orientations of the pipes, and other factors.
2. Description of Related Art
Pipefitters and related workers are often confronted with the need to connect two existing runs of pipe to one another, where the angle between the two pipes is predetermined by the existing locations of the two pipe runs. The angle between the pipes is of course critical, in that it determines the angle of the elbow which must be used to interconnect the two pipes.
In many, or perhaps most, cases, the angle between the two existing pipes is something other than that of a conventional elbow of thirty, forty five, or sixty degrees. This angle must of course be measured precisely in order to fabricate an elbow of the proper angle. Such custom fabrication may be encountered in many different environments, but is particularly true in the energy production industry in coal, gas, and petroleum processing plants and refineries, where large diameter pipe runs must be modified from time to time as different processing lines or tanks are installed or modified, etc.
Accordingly, a need will be seen for a pipefitter""s protractor which can precisely measure the angle between two existing pipes. The present protractor accomplishes this by centering the protractor along the centerline of one of the pipes, with a string or line extended to the center of the second of the two pipes. The resulting angle of the line on the protractor, indicates the angle of the elbow required to connect the two pipes. The present protractor is also linearly adjustable along the length of the pipe to which it is secured, thus also providing an indication of the length of pipe needed from the end of the existing pipe to the angular center of the elbow.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,334,422 issued on Nov. 16, 1943 to Carl H. Lehnus, titled xe2x80x9cPipe Protractor,xe2x80x9d describes a device for cutting or marking pipes or cylindrical objects about their circumferences. The Lehnus device comprises a bracket which is secured to a pipe or the like by a chain which is secured around the pipe. A protractor is provided at the end of the bracket, with the protractor having a series of interconnected links extending therefrom. The links are fixed in one plane, and can only be adjusted in a plane passing around the pipe. The protractor is adjusted at the desired angle and the links are extended around the pipe, with the cutting or marking line falling along the plane defined by the links. This device cannot be extended to another pipe in order to determine the angle between two pipes, as provided by the present invention.
U.S. Pat. No. 2,466,464 issued on Apr. 5, 1949 to James W. Moore, titled xe2x80x9cPipe Pattern Maker,xe2x80x9d describes a device for marking the side of a pipe or other cylindrical object to join a similarly shaped object thereto. The Moore device comprises a series of plates with a series of holes formed therethrough to define various diameters, and accepting series of pins. The pins are arranged to define a circular pattern of the desired diameter, and a center reference pin with a protractor at the distal end thereof serves to measure the desired angle. The pins serve to mark the elliptical pattern on the subject pipe, for joining the other pipe thereto. As in the device of the Lehnus ""422 U.S. Patent discussed immediately above, the Moore device cannot measure an angle between two pipes, but only marks one pipe after the angle is known.
U.S. Pat. No. 2,502,660 issued on Apr. 4, 1950 to Joseph A. McLean, titled xe2x80x9cDevice For Scribing Pipes,xe2x80x9d describes another device for marking a line about a pipe for cutting or other work. The McLean device comprises a protractor which is secured rigidly along the length of the pipe, by a pair of bands which extend about the pipe. A line is extended from the origin of the protractor, around the pipe, and back to the origin, with the angle of the line being adjusted as desired to position the line for marking or cutting the pipe. Thus, the McLean device is more closely related to the device of the Lehnus ""422 U.S. Patent than to the present invention, as the McLean device cannot be used to determine an angle between two pipe runs, which is the function of the present pipefitter""s protractor invention.
U.S. Pat. No. 2,717,454 issued on Sep. 13, 1955 to Rudolph O. Sekki, titled xe2x80x9cPipe Layout Gauge,xe2x80x9d describes a device for scribing a pipe for cutting through a plane passing through the pipe. The device comprises a laterally expandable saddle which is placed over the pipe. A pair of separable semielliptical plates are secured around the pipe and to the saddle, and aligned as desired according to a protractor on the side of the saddle. The cutting line is marked along the plane of the semielliptical plates. The Sekki device cannot measure an angle between two pipe runs for fabricating an elbow joining the two, as provided by the present invention. The Sekki device will thus be seen to be more closely related to the devices of the Lehnus ""422 and McLean ""660 U.S. Patents discussed above, than to the present invention.
U.S. Pat. No. 2,827,708 issued on Mar. 25, 1958 to Evans A. De Peu, titled xe2x80x9cPipe Cutting Indicator,xe2x80x9d describes two embodiments of a device for laying out a cutting line around the circumference of a pipe. As in the Lehnus ""422 and Sekki ""454 U.S. Patents discussed above, De Peu provides a saddle or shoe which is seated along the surface of the pipe. A protractor extends from the saddle, either across or parallel to the plane of the pipe, depending upon the embodiment. A guide extends from the protractor and is adjusted to the desired angle for marking or cutting the pipe in the desired plane. As in the other devices discussed above, the De Peu device cannot measure an angle between the centerlines of two intersecting pipe runs for fabricating an elbow joining the two, as provided by the present invention.
U.S. Pat. No. 2,899,750 issued on Aug. 18, 1959 to James O. Becroft, titled xe2x80x9cMeasuring Device For Pipes,xe2x80x9d describes a device for determining the setback from the intersection of the centerlines of two pipes, for fabricating or assembling an elbow connecting the two pipes. The Becroft device comprises a pair of arms arcuately secured together at a mutual origin point. One of the arms includes a scale for different pipe diameters, while the other arm includes a scale indicating the setback from the intersection of the centerlines of the pipes. Neither of the scales of the Becroft device includes a scale calibrated in degrees of arc for measuring an angle, as provided by the present invention; this must be accomplished in order to determine the angle of the elbow, which problem Becroft does not address.
U.S. Pat. No. 3,038,261 issued on Jun. 12, 1962 to Griffin C. Blain, titled xe2x80x9cPipe Layout Apparatus And Method,xe2x80x9d describes an apparatus for determining the layout for a pipe used for interconnecting two non-coplanar pipes. The Blain device is relatively complex, comprising two separate base components which fit respectively on each pipe. One of the base components includes a protractor. A line is extended between a pivot for the protractor and a similar pivot extending from the base component of the opposite pipe, and the angle of the line relative to the protractor is noted. At this point, another device such as the device of the Lehnus ""422 U.S. Patent discussed further above, must be used to lay out the cutting angle, i.e., half of the angle indicated by the interconnecting line and protractor. All of the above difficulties are easily overcome with the present protractor invention, merely by welding (or otherwise attaching) a stock elbow of the appropriate diameter to one of the pipes, with the open end of the elbow in alignment with the second pipe. The present pipefitter""s protractor may then be used to develop a second elbow to connect the second pipe to the first elbow. The result is a joint having two elbows or angles, which is the same finished configuration developed with the complex device of the Blain U.S. Patent. Moreover, Blain does not provide any means of aligning his device with the centerline of either pipe, nor for adjusting the position of his protractor axially along the centerline of one of the pipes, as provided by the present invention for measuring the angle required for construction of an elbow.
U.S. Pat. No. 3,060,587 issued on Oct. 30, 1962 to William Picken, titled xe2x80x9cPipe Bending Gauge,xe2x80x9d describes a device which is clamped to the side of a pipe parallel to the plane of the bend to be made in the pipe. A protractor indicates the degree of bend produced during the bending operation. The Picken device is also adjustable to accommodate incremental bends over a section of pipe to complete the total angular change of direction of the pipe. The Picken device is thus directed to measuring the bend angle in a pipe undergoing bending, and is not adapted for use in measuring the angle between two angularly displaced pipes for constructing an interconnecting elbow, as provided by the present invention. The Picken device must be offset from the centerline of the pipe undergoing the bending, and cannot be aligned with the axis of the pipe, as provided by the present pipefitter""s protractor.
U.S. Pat. No. 3,200,505 issued on Aug. 17, 1965 to Ralph G. Hedges, titled xe2x80x9cProtractor Guide For Bending Pipes,xe2x80x9d describes a device serving much the same purpose as the device of the Picken ""587 U.S. Patent discussed immediately above. The Hedges guide merely measures the incremental series of bends formed in a pipe to complete the desired total bend. It cannot measure an angle between two separate pipes, as provided by the present invention. Moreover, Hedges does not describe any specific means of aligning his protractor with the pipe being bent, other than describing xe2x80x9calignment barsxe2x80x9d secured to each side of the protractor. Hedges does not disclose any means of positioning his protractor concentrically with the pipe, as provided by the present invention.
U.S. Pat. No. D-363,239 issued on Oct. 17, 1995 to Steven E. Spirer et al., titled xe2x80x9cCutting Guide Protractor,xe2x80x9d illustrates a design having a protractor with an elongate arm and what is apparently a clamp, extending therefrom. The jaws of the clamp are relatively shallow; it does not appear that the device is capable of attaching to a relatively large diameter pipe. In any event, the elongate arm appears to be angularly adjustable, along with the protractor, relative to the clamp. However, no means is apparent for aligning the arm concentrically with the axis of a pipe, nor for positioning the protractor outwardly from the pipe and along the centerline of the pipe, as provided by the present pipefitter""s protractor invention.
Finally, British Patent Publication No. 2,139,365 published on Nov. 7, 1984 to Timothy C. Dearman, titled xe2x80x9cPipefitter""s Protractor,xe2x80x9d describes a device which is used to hold two separate welder""s squares for convenient manipulation. The Dearman device permits the two squares to be clamped to the protractor element, rather than being held by hand while attempting to measure an angle therebetween. Dearman does not provide any means for either concentrically or peripherally securing his device to a pipe, nor for measuring the angle between two separate pipes for fabricating an elbow joining the two pipes, as provided by the present pipefitter""s protractor invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention comprises a pipefitter""s protractor, for measuring the angular difference between two pipes (or similar elongate structures) to be joined by an intermediate elbow. The present protractor permits the angle to be measured precisely, by placing the protractor along the extended centerline of one of the pipes and running a line to the centerline of the other pipe. An elbow having the required length for each leg and the proper included angle, may then be fabricated to join the two pipes.
The present pipefitter""s protractor apparatus includes a graduated pipe attachment bar, having a center origin point. The scale extends to each side of the origin, with a pipe rim attachment clamp provided to each side of the origin. The pipe to which the device is to be attached is squared, i.e., the rim is made normal to the axis of the pipe, and the pipe attachment bar is secured to the rim of the pipe with the scale origin concentric with the pipe centerline.
A protractor extension bar or arm is secured to the center of the pipe attachment bar, and extends normal thereto along the extended centerline of the pipe. The protractor is secured to the extension arm, and a line is run from the origin of the protractor (which is located essentially along the extended centerline of the pipe) to a point along the centerline of the second pipe. The position of the protractor is adjusted along the protractor arm, to position the protractor origin in alignment with the centerlines of both pipes.
At this point, the angle of the line is read on the protractor and the distance from each pipe end is measured. An elbow having the required leg lengths and angle is then fabricated from these measurements. The present protractor may be used for related purposes as well, if so desired. For example, the pipe attachment bar may be used as a trammel bar or beam compass, by clamping a pivot in one of the clamps and a marker or scribe in the other of the clamps, and adjusting the clamps linearly along the scales as desired to mark or scribe a circle or arc of the desired diameter.
Accordingly, it is a principal object of the invention to provide a pipefitter""s protractor for accurately measuring the angle between the centerlines of two pipes, for fabricating an elbow joining the two pipes.
It is another object of the invention to provide a pipefitter""s protractor in which the protractor has an origin which is adjustably positionable at the intersection point of the centerlines of the two pipes to be joined.
It is a further object of the invention to provide a pipefitter""s protractor in which the protractor is secured to an attachment arm concentric with the centerline of one of the pipes, with the attachment arm rotationally mounted to a pipe attachment bar for allowing the plane of the protractor to swivel to lie coplanar with the plane defined by the two pipes.
Still another object of the invention is to provide a pipefitter""s protractor including a pipe attachment bar which is convertible for use as a trammel bar for marking circles and arcs.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.